知道函数值范围值求出自变量的范围值,可以这样来处理:
>> syms x
>> y=-1;x1=solve(y==sin(x),x);
>> y=1;x2=solve(y==sin(x),x);
>> x=x1:pi/10:x2;
>> plot(x,sin(x))
>> xlabel('x'),ylabel('y')
运行结果
clear;clc;x=linspace(0,15,16);y=25*x;y1=0.2*0.0045*x.^5-0.25*0.1517*x.^4+1.7807/3*x.^3-0.5*8.3483*x.^2+29.2147*x;L=(y-y1)*6.5/3;plot(x,L);holdon;x160=interp1(L,x,160);plot(x160,160,'r.');text(x160,160,sprintf('(%g,%g)',x160,160));